As is well known to those skilled in the art, deposits form in the combustion chamber of an internal combustion engine as a result of incomplete combustion of the mixture of air, fuel, and oil. This is particularly true in the case of cars which operate on unleaded fuels. After a few thousand miles of operation, the deposits are of such a level that the performance of the engine decreases. Specifically, when the charge gasoline is of constant octane number, the power output decreases. In order to maintain the power output at a predetermined desired level, it is necessary to increase the octane number of the fuel over the course of time. This Octane Requirement Increase (ORI) is clearly undesirable.
It is an object of this invention to provide a fuel boiling in the gasoline boiling range which is characterized by a decreased octane requirement increase. Other objects will be apparent to those skilled in the art.